Association between Chronic Knee Pain and Psychological Stress in Those over 50 Years of Age: A Nationwide Cross-Sectional Study Based on the Sixth Korea National Health and Nutrition Examination Survey (KNHANES 2013–2015)

Chronic knee pain (CKP) can degrade the quality of life and cause dysfunction, resulting in the loss of independence. Psychological stress not only affects physical and mental health but is also a risk factor for CKP. In this cross-sectional study, we analyzed data from the sixth Korea National Health and Nutrition Examination Survey (2013–2015), and investigated the association between CKP and psychological stress of the Korean general population. The CKP status was determined based on survey responses of self-reported knee pain lasting for more than 30 days during the last 3 months. Psychological stress was classified as none, mild, moderate, or severe. The association between CKP and psychological stress was analyzed using multiple logistic regression analysis considering co-variables and demographic data. Logistic regression analysis adjusting for co-variables indicated that the risk of CKP increased with an increasing degree of stress, from mild (OR = 1.65, 95% CI 1.35–2.03, p < 0.001) to moderate (OR = 2.00, 95% CI 1.56–2.57, p < 0.001) and severe (OR = 3.02, 95% CI 2.08–4.37, p < 0.001). A significant association between the risk of CKP and psychological stress was identified. Therefore, when evaluating patients with CKP, it may be helpful for clinicians to check the degree of stress.